Most other application icons should go to their home modules instead of residing in kdelibs - this not only makes for a better overview but also reduces disk space in case not all modules are installed. And, of course, prevents icons being misused for wrong usages.

To do for Oxygen

Icons that are in the spec, but not yet in Oxygen's apps/ (after renaming) so they need to be added. Descriptions taken from the specification.

preferences-desktop-multimedia
The icon used for the desktop's multimedia preferences.
preferences-desktop-theme
The icon used for the desktop's theme preferences.

To do for Oxygen - not in the spec

Icons that are not specified and do not currently exist as well, but are needed for KDE applications (and not blatantly obvious). Yes, I am aware that some of those are bad (if not outright evil) names. That comes from preferences-desktop-peripherals being classified in the "desktop" preferences subgroup, which is very wrong imho. We need to fix this in the spec (see the suggestions of the categories page), but until then, I stay with specification conform names.

preferences-desktop-display
The icon for the "Display" KCM.
preferences-desktop-effects
The icon for the "Desktop Effects; KCM. (New in KDE 4.)
preferences-desktop-gaming
The icon for the "Joystick" KCM.
preferences-desktop-launch-feedback
You can guess. Really, it's easy.
preferences-desktop-mouse
The icon for the "Mouse" KCM.
preferences-desktop-panel
The icon for the "Panels" KCM.
preferences-desktop-user
The icon for the "About me" KCM in KDE 4's System Settings
(which was named "Password & User Account in KDE 3).
preferences-system-login
The icon for the "Login Manager" KCM.
preferences-system-power-management
The icon for the "Power Control" KCM. (Although I'm not sure if
this will still exist for KDE 4, at least in its current form.)
preferences-system-network-share
The icon for the "File Sharing" KCM.
preferences-system-session
The icon for the "Session Manager" KCM.
(This icon also exists in the Tango set.)
preferences-system-splash
The icon for the "Splash Screen" KCM.

Optional icons

We don't absolutely need those because they are covered by fallbacks: if these icons don't exist, they've got a sensible fallback.

preferences-desktop-display-randr
The icon for the "Size & Orientation" KCM.
preferences-desktop-keyboard-khotkeys
The icon for the "KHotKeys" KCM.
preferences-desktop-panel-taskbar
The icon for the "Taskbar" KCM.
preferences-desktop-user-smartcard
The icon for the "Smartcards" KCM.
(Was "identity" in KDE 3, and is really not necessary.)
preferences-system-solid
The icon for the "Solid" KCM. (New in KDE 4.)
preferences-system-windows-effects
The icon for the "Window Effects" KCM. (New in KDE 4.)
preferences-system-windows-decoration
The icon for the "Window Decorations" KCM.
preferences-system-windows-specific
The icon for the "Window-Specific Settings" KCM.

Icons in Tango, but not in the spec

We don't need to have those, but if we do they should be named this way:

internet-group-chat
For a possible generic instant messager icon.
*Very* optional though, as we already have branded
Kopete and Konversation icons.
internet-mail
We already have this from the previous "kmail" icon.
internet-news-reader
Instead of "knode".
internet-web-browser
For a possible generic browser icon. *Very* optional though,
as we already have a branded Konqueror icon.
office-calendar
We already have this from the previous "korganizer" icon.
preferences-desktop-assistive-technology
Tango does this as preferences-desktop-accessibility
plus an emblem-style gear icon at the lower right.
Hardly necessary to have.
preferences-desktop-sound
Go Phonon go. (Done.)
preferences-system-network-proxy
We do have proxy settings in KDE 3, this might make sense.
preferences-system-session
The icon for the session management settings.
preferences-system-windows
Done.
system-installer
Adept, Yast, Pirut, Smart, or whatever else is out there.
system-users
Seems to fit KUser or Guidance's "User Management" module.